


never let me go

by avosettas



Category: Undertale (Video Game)
Genre: ...probably, Aftercare, Background Bad Sanses Poly, Dacryphilia, Dom/sub, Dreamtale Nightmare Sans (Undertale), Dreamtale Nightmare Sans/Dreamtale Sans | Dream (Undertale), Dreamtale Sans | Dream (Undertale), Ecto-Vagina (Undertale), Exhibitionism, Fingerfucking, M/M, Multiple Orgasms, Orgasm Delay/Denial, Overstimulation, Praise Kink, Sibling Incest, Subdrop, Subspace, Vaginal Fingering, i mean. maybe??
Language: English
Status: Completed
Published: 2021-02-19
Updated: 2021-02-19
Packaged: 2021-03-15 02:21:02
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,338
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29552031
Author URL: https://archiveofourown.org/users/avosettas/pseuds/avosettas
Summary: Killer and Dust had been needling at Dream for weeks to demonstrate his little “murders are bad, orgasms are good” idea. They probably hadn’t thought he’d agree, nor that he’d demonstrate ofNightmareof all people. But Dreamhadagreed.
Relationships: Sans/Sans (Undertale)
Comments: 10
Kudos: 185





	never let me go

**Author's Note:**

  * For [Cypress_Leaves](https://archiveofourown.org/users/Cypress_Leaves/gifts).



> THIS IS PROBABLY THE HORNIEST THING IVE EVER WRITTEN AND I'M GOING TO PASS OUT NOW OK BYE
> 
> [based on this thread by askellie, withtheworms, and enneadodeca](https://twitter.com/enneadodeca/status/1299224406703702016?s=21)
> 
> also thank you hella for coming up w a safeword for nightmare so i didn't end up using something apple related lmao

“Spread your legs wider, please,” Dream says softly, right beside his aural canal. Low enough that it’s possible that the others, mostly staring unabashedly, probably didn’t hear. 

Nightmare obeys him slowly, aided by Dream’s hands on his thighs as he leans down to reach. He doesn’t seem to mind that Nightmare is sprawled over his lap, practically slumped against his chest with his tentacles pressed against his ribs; rather, he seems pleased as punch to have his counterpart in this position, bare for the others to see. 

He doesn’t chance looking at them as he splays his legs, as wide as his joints allow, but he does prod slightly at their emotions, looking for anything that feels disappointed. All he feels from them is arousal, though - even Cross, who’d been so purple in the face when they’d started that Nightmare had feared that he would pass out. 

Dream pulls him upwards a bit, resting Nightmare’s rump on his lap so as to be able to reach him better. He coos a bit, fingers barely skirting Nightmare’s pseudo-skin as he drops a hand between his legs. There’s a tinge of amusement of in his voice as he asks, “Ready to help me demonstrate, Night?” 

Nightmare’s breath stutters a little, hands fisting in the bedspread. He’d thought they’d already started - Killer and Dust had been needling at Dream for weeks to demonstrate his little “murders are bad, orgasms are good” idea. They probably hadn’t thought he’d agree, nor that he’d demonstrate of _Nightmare_ of all people. But Dream _had_ agreed, and he’d had Nightmare repeat a safeword back until it felt like gibberish in his mouth. 

And then he’d started _demonstrating_ , and now Nightmare was here, already breathing heavily from his attentions. 

“I thought we had already started,” he responds finally, a little breathless. Dream’s hand is still hovering between his legs, not quite touching. He laughs a bit, a soft chiming noise like a bell in the wind, and uses his other hand to tilt Nightmare’s head back and kiss him. 

When they part, Dream smiles, though there’s something mischievous about it. “Oh, but that was hardly even foreplay, Night! This is where we begin the _real_ demonstration.” 

He can’t stop himself from jolting when Dream slowly drags his index finger up his slit, hardly even dipping into his folds. Dream hums into his shoulder as he repeats the action, with only slightly more pressure. 

The third time he does it, Nightmare tries to convince himself that he isn’t above begging, but then he remembers that the others are there. 

He sneaks a glance at them as Dream continues - anything to distract from the maddening frustration of being _barely_ stimulated. Horror seems the most composed, if only because he also has the least magic, his flush barely showing up on his skull. His single eyelight is focused on a spot that isn’t _quite_ Nightmare, but he glances up often enough that he probably isn’t missing anything. Cross is much the same, with his bright purple flush and his hands fisted in his shorts. 

Killer is the deviation from the rule - he’s as shameless as ever, of course, palming the telltale bulge in his shorts with lidded sockets. Even without his eyelights, it’s obvious his gaze is trained directly on Nightmare, right where Dream is touching him. And Dust is possibly worse, leaning forward in his chair with his tongue lolling out slightly.

His attention is dragged back to Dream when his brother’s hand leaves him - he’s decided to pull off his gloves before continuing, it seems. Nightmare can’t blame him, really, but he’s also _fucking desperate_ for anything. 

Dream places his gloves beside them in a little pile of yellow leather, and then one hand returns to Nightmare’s hip. After a moment, his other hand descends as well, one finger coated in a thin layer of what can only be Dream’s spit, golden-tinted as it is. His legs spasm when that finger _finally_ presses to his clit, and, with the barest pressure, Dream begins rubbing circles into it. 

Nightmare makes a soft sound, a bitten off moan, and unconsciously bucks into the touch. Behind him, Dream hums appreciatively, nuzzling into his neck. 

“You’re so sensitive today,” he murmurs, slipping his finger downward again. “And wet,” he adds as he goes back to Nightmare’s clit. Nightmare moans softly, mostly muffled by his clenched jaw. 

The sound makes Dream laugh, and his grip on Nightmare’s hip tightens incrementally. “Don’t hide your noises from me,” he orders, though his tone is gentle. “Or from them.” 

Nightmare cringes slightly at the reminder of the others, training his gaze onto the ceiling, but he spreads his legs again when Dream nudges at them with his own. “Nightmare,” he croons, squeezing his hip once more before letting go, stroking up his body to cradle his jaw. 

“Open,” Dream says, his thumb already on top of Nightmare’s teeth. 

As soon as Nightmare obeys, Dream wedges that thumb into the corner of his mouth, keeping it open enough that no sound is muffled. At the same time, he presses harder on Nightmare’s clit, and the resulting keen rings through the room. 

He closes his eye, too embarrassed to look at the others, even though he can feel that they’re enjoying the show Dream is directing. He pants around Dream’s thumb as the hand at his cunt shifts, three fingers rubbing at him instead of the previous one. 

“Tell me when you’re close,” Dream murmurs, the command almost lost beneath Nightmare’s panting. He nods jerkily, arching to press himself against Dream’s hand. Behind him, his brother simply chuckles. “Keep your mouth open, now,” he adds as he removes the hand wedged in Nightmare’s mouth, using it press him back against the bed by the soft false flesh of his belly.

“Cl-close,” Nightmare stutters obediently after another few moments. Dream presses a kiss to his cervical vertebrae as he moans, no longer muted by himself nor the makeshift gag of Dream’s thumb. His hand slows slightly before pulling away, and Nightmare lets out an actual whine, legs twitching unconsciously, as if trying to keep the other from stopping. 

Dream pins them wide open, though, with his own legs hooked beneath Nightmare’s patellae. Nightmare groans at his musical giggles, although he’s unable to focus on much aside from the fading pleasure. His pussy clenches repeatedly around nothing, as if bemoaning the loss of touch. Dream notices, because of course he does, somehow attuned to his brother’s every need, and he makes a wordless, appreciative noise, trailing his finger around Nightmare’s entrance too lightly to be stimulating, before once again withdrawing. 

Dust’s rasping voice cuts through the thickening fog suddenly. “i have a question.” 

“What is it, Dust?” For all that he has Nightmare held in his lap, debauched by his touch, Dream sounds like a teacher. His thumbs rub at Nightmare’s hips as he hooks his chin over his brother's shoulder with an easy smile, most likely to focus more closely on the others. 

All Nightmare can really focus on is the fact that one of Dream’s hands is still sticky with his slick. It’s disgusting, and he wants Dream to _touch him again_ -

“i thought the idea was that ‘orgasms were good’,” Dust says. “but you didn’t let him cum.” 

“I’ll let him cum later,” Dream replies, the threat of his words overshadowed by his cheerful tone. “If he’s good.” 

As he speaks, his hand snakes back downward, and Nightmare groans when Dream presses one finger to his clit, as if he’s testing how much his brother has calmed from his previous edge. 

“If you ask me really nicely,” Dream continues, quieter now, like he’s sharing a secret. “Maybe it’ll be sooner rather than later.” His finger leaves Nightmare’s clit again, and he hushes the immediate groans of protest. A moment later, the same finger circles Nightmare’s entrance, before pushing in up to the knuckle. 

Nightmare throws his head back onto Dream’s shoulder with a low groan, unheeding of how he must look as he spreads his legs wider for it. He’s well over the shame at this point, even rolling his hips upward to try and press Dream’s finger deeper into him. 

“No,” Dream admonishes, though he doesn’t push Nightmare back down. “Behave yourself, please.”

The sad thing is that Nightmare listens, forcing his hips to rest back on his brother's lap. Dream rewards him with a soft hum, just as he begins to thrust his finger shallowly. His other hand moves from Nightmare’s hip again, and he twitches when two of Dream’s fingers spread the folds of his cunt wide, exposing him even further. 

Someone - not Dream, and he only knows that because it was too far away to have been Dream - says something, the sound coming deep from their throat and only registering as _admiring_ in Nightmare’s arousal-fuzzed mind. 

Dream responds in kind. “He is, isn’t he?” At the same time, he strokes gently over Nightmare’s clit with one of his free fingers, the sensation amplified now that he’s uncovered the nub. Nightmare moans, the sound stuttering when Dream begins to rub at him in earnest again, and when he jerks his head back once more, the sudden eye contact startles him. 

He can’t see much of his brother besides his eye sockets, but they’re rounded with mirth, and his eyelights are bright and golden. He groans questioningly when Dream smiles wider at him, evident by the crinkle beside his sockets. 

“Killer was just commenting on how pretty you look, spread out like this. Dripping all over my hand,” Dream tells him, pressing a teasingly-chaste kiss to his skull. Nightmare whimpers at the soft touch, before breaking into another moan as Dream plunges his penetrating finger deep into his cunt. 

It’s so good, but so much _more_ than everything else Dream has done, and Nightmare gasps wetly as the finger inside him curls slightly, the sudden pleasure making him jerk. 

“Don’t cry,” Dream says placatingly, as if Nightmare can help it, although truth be told he hadn’t noticed the tears before his brother mentioned them. Dream nudges Nightmare’s face with his own chin, kissing beneath his eye socket when it’s close enough to reach, continuing even as he works a second finger into him. 

Nightmare sobs, and the sound is broken and ugly in his aural canals. Dream hushes him, as he has repeatedly. “Sh, sh,” he says, little nonsense noises that make Nightmare feel better for no good reason, even as his fingers slow incrementally. “Are you close?” 

He nods, even though he knows Dream is going to stop again, and leave him empty. And he does, though this time he wipes both hands on the comforter beneath them before bringing them up to hold Nightmare’s face. His skull feels full of haze, and the only thing he can focus on besides the fading pleasure is Dream. 

Dream smiles fondly at him, nuzzling at his skull a bit. “Talk to me,” he murmurs, his voice sharp against the soft, dulled edges Nightmare’s mind. Dream holds the shears, sharp and precise to cut away the wool that grows uncontrollably to cloud his thoughts. And he’s the hand spindle and the loom and the spinner and the weaver, too, making it all into something coherent when Nightmare isn’t able to. 

And Nightmare isn't able to, not right now, only managing to twist himself slightly in Dream’s lap and lean towards the hands on his face. His hands grasp at his brother’s shirt, and his tentacles wind around him unconsciously, as if to be sure he won’t leave. Dream strokes his cheeks lightly, golden eyelights flickering as they search his expression. 

“Do you want me to keep going?” Dream asks finally, and Nightmare nods silently, wordless but still beyond grateful that Dream knows him well enough not to ask outright if he needs to use his safeword. It’s burned into his mind, but he’s still reluctant to use it, and Dream knows that, of course he does. Even saying “yes” and “no” is hard, sometimes, but Dream knows that, too. 

He chuckles a bit, still cupping Nightmare’s skull, holding him so gently that it’s as if he’s trying not to crush the petals of a delicate flower. Nightmare closes his eye when Dream kisses away his tears once more, torn between leaning into that, or into the stroking motion of his brother’s thumb on his opposite cheek, right below his blind eye.

“I’ll let you cum this time,” Dream promises, “if you tell me what your safeword was.” 

Of course there’s a condition, but the thought barely even surfaces before it flits out of his mind again. "Eclipse,” Nightmare tells him dutifully, though his voice is soft and strained from use. Dream praises him wordlessly, nuzzling him slowly, still focusing his actions on the tear-stained rim of Nightmare’s eye socket. 

Dream rearranges Nightmare slightly, pulling his back flush to his own chest and twining their legs together once more, so that he can keep his brother’s legs spread with his own knees. He doesn’t begrudge Nightmare’s tentacles the privilege of winding loosely around his waist, though he does pry his hands from where they’re tangled in his shirt, and redirects them to grasp onto the comforter once more. 

“Pay attention,” he directs the others as he situates Nightmare’s hands, giving the right one a last squeeze before placing it onto the bed. 

“...will he get to… cum this time?” Horror asks slowly, and though the tiny, lucid part of Nightmare’s mind knows he can’t help it, the larger, foggy part is begging him to talk faster. His eyelight is blown wide and focused on Nightmare, now, earlier shyness forgotten.

“Mhm,” Dream hums, trailing his fingers in the crevice between Nightmare’s ecto-body and his lowest floating rib. Nightmare clenches his fists in the bedspread again as he continues, “He’s been awfully good, don’t you think?” 

“...yeah,” Horror agrees quietly. There are murmurs of assent from Cross and Dust, too, as well as a louder affirmative from Killer. Nightmare barely looks at them, though; his mind is broken record, skipping their tracks and repeatedly going _Dream, Dream, Dream_. 

As if Dream can hear it, he laughs, and brings his hand down between Nightmare’s legs again, rubbing through his folds with his knuckles. Unconsciously, Nightmare spreads his legs, though they can't go much further, already spread as far as possible by Dream's knees. But the action makes Dream purr, pleased, and he basks in the feeling of the soft vibration behind him. 

"You've been so good today," he says, the words coming out like a sigh. He unfolds his fingers, pressing one, and then another into Nightmare. Nightmare is loose-limbed against his brother; his bones feel like jello, and all he manages is a soft moan and a slight curl of his toes. 

Dream laughs again, and his fingers curl as he murmurs, "Oh, I love seeing you like this. All relaxed, not so uptight or stressed…" His other hand drifts to Nightmare's pussy from its spot near his ribs. Dream rests his index finger just above Nightmare's clit, caressing too lightly to be stimulating, though the feeling is still pleasant, especially coupled with the fingers of his other hand buried deep in Nightmare's cunt. 

One of the others says something - agreeing with Dream, probably. Nightmare is too busy forcing his hips to stay where they are, even though he could probably rock against Dream's finger if he moved enough. But thankfully, his brother is known for mercy, and when Nightmare groans next, he presses his finger down harder, though he barely moves it. 

Even so, it's better than his teasing stroking. 

"Oh, wow," Dream's tone is appreciative, though Nightmare can't process what for. "You're making a puddle, Night." 

The world is too blurred for Nightmare to be embarrassed, and he thinks he lost the ability to feel shame somewhere around the first time Dream denied him release. He doesn't dwell on it; instead he arches, mewling when Dream's fingers curl and stroke against his walls. 

When they uncurl, Dream adds a third finger, and Nightmare nearly sobs when he finally starts fucking him with them, slow but deep. Dream doesn't scold him when his hips buck upwards this time, though he does curl his legs tighter around Nightmare's, pulling his brother back down. 

Dream's other hand finally moves, rubbing firm circles that match the pace of his penetrating fingers, and it sends Nightmare careening over the precipice, body tensing and toes curling. Dream leads him through it, and though Nightmare doesn't register his words, his gentle, soothing voice is home. 

He continues even when Nightmare begins twitching and jerking out of sensitivity, though his pace slows further and the hand on Nightmare's clit stops almost completely, only pressing firmly every so often. 

"The boys aren't quite sure that the lesson stuck," Dream tells him. The soft, ever-present smile on his face is absolutely unapologetic. "Do you think you could once more?" 

Nightmare nods without thinking about it, and Dream leans down to nuzzle at him. Something wet spreads across his cheek with the motion, though it takes him a moment to realize he's started crying again. But with Dream praising him, he doesn't really think it matters. 

Dream begins moving his hands again even as he continues nuzzling Nightmare, picking up his previous slow pace. Nightmare spasms beneath his careful hands, every touch making him shake. Every touch is more pronounced in the face of his previous orgasm, and surprise that he hasn't cum again yet flits through his mind. 

It's gone in a flash, because Dream presses the flat of his distals to some sweet spot, and this time Nightmare wails as he cums, arching so hard that the stretch makes his back ache. Again, Dream guides him through it, quiet words a stark contrast to Nightmare's panting. Eventually, Dream's hands leave him, and for a moment, it's like a string's been cut, letting him float off. But his brother returns just as quickly, pressing soft kisses to his face. 

Everything that follows feels blurry. He thinks they moved; he definitely didn't walk, but Dream might have moved him, or one of the others. And everything feels cold, and someone's bones are rattling. 

He startles when a warm washcloth passes over his arm, but it's only Dream, armed with both the cloth and a bowl of warm water. He smiles before returning to his work of scrubbing at Nightmare, attentively running the cloth over every bone. Every so often, he raises a hand to Nightmare's face, and strokes beneath his eye socket. 

It's not until Dream is setting his cleaning supplies on the nightstand that Nightmare connects the rattling bones to himself. The conclusion makes him aware that he's crying, too, and that only makes the rattling worse. 

Dream turns at the sound, resting one hand on Nightmare's cheek as he yanks the quilt up. There's a brief moment where Dream disappears, but he returns just as quickly, armed with a second blanket that he spreads on top of the quilt before climbing under both beside his brother. 

"I'm so proud of you," he mumbles, holding Nightmare tight. It mitigates the rattling, just a bit; the blankets combined with Dream's embrace are pleasantly warm. 

Nightmare's reply is a strange, croaking sound, the words lost beneath the stupid tears that he can't seem to control. Dream wipes them away again, and repeats, "I really am proud of you, Night." 

It makes Nightmare cry harder, and though he's mentally cursing the tears, still unable to form words, Dream doesn't seem to mind. He doesn't push or prod; he only intermittently repeats to Nightmare how proud he is, and it's enough. 

(And even if wasn't, Dream knows that there are four other skeletons who could certainly find something to say that would be enough for his brother. But he also knows that that can wait until tomorrow, after Nightmare gets some rest.)

**Author's Note:**

> twitter @avosettas
> 
> edit 2/20/2021: please don't ask me for a follow-up/other POV because it isn't happening and all asking does is stress me out. thanks yall


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